The manufacturing process for forming a display panel (e.g., a liquid crystal panel) on an insulating substrate such as a glass substrate includes steps prone to generating static electricity, e.g., plasma caused by dry etching or static electricity caused by an air knife for use in removing an etchant used for wet etching. The generated static electricity charges some scanning signal lines and data signal lines, with the result that a high voltage is applied between signal lines that are insulated from each other, and when the voltage exceeds a dielectric strength of an insulating film, electrostatic discharge (ESD) occurs. When the ESD occurs, the insulating film, which insulates adjacent conductors, is broken, whereby a short circuit occurs between signal lines that are to be insulated, with the result that the liquid crystal panel is caused to operate abnormally or misoperate.
Therefore, an electromagnetic wave detection device described in Patent Document 1 includes a protection circuit provided outside a detection portion having photoelectric conversion elements formed therein, and the protection circuit includes input/output terminals formed on scanning signal lines and data signal lines, conductor lines extending outwardly from the input/output terminals, and a common line coupling the conductor lines outside the input/output terminals. This prevents variations in operating voltage among thin-film transistors and physical breakage of the thin-film transistors, even if the scanning signal lines and the data signal lines are electrostatically charged.